High-Fidelity Simulation of Failure Mechanisms in IM7/8552 Composite under Crushing Load

Kurzfassung

Numerical finite-element simulations can serve as a tool to evaluate crushing processes of fibre reinforced plastics. They provide insights that extend the possibilities of experimental testing, such as the evaluation of local material failure during the crushing process. Crushing processes are driven by complex material failure mechanisms. High-fidelity modelling techniques are used to accurately reproduce these failure mechanisms [1]. In addition, physics-based material models are able to make simulation models more universally valid and less dependent on individually adjusted parameters. This study aims to develop a high-fidelity simulation model capable of performing an in-depth analysis of inter- and intra-laminar damage and post-failure behaviour. To ensure a physically valid basis, the objective was to use a physically based modelling approach and avoid empirical parameters. The simulation model was implemented in LS-DYNA, employing a combination of solid and cohesive elements to be able to accurately capture interlaminar failure. Material behaviour was modelled using the physically based continuum damage model MAT_262 developed by Maimi et al. [2]. The simulation approach was validated against experimental tests on omega segments made from IM7/8552 with a stacking sequence of [90/45/-45/0]2S and a 45° chamfer trigger [3]. Preliminary results show that, despite the higher level of detail and more complex failure and damage models in the current approach, adjustments to material parameters, such as the fracture energies, were necessary to establish a stable progressive crushing behaviour. This suggests that the inherent simplifications of current numerical methods are too significant to fully capture the complexity of progressive crushing without any parameter tuning. Future work will focus on integrating this simulation model with MAT213 to analyse the influence of thermal effects on the crushing process.

[1] H. Böhm, J. Richter, J. Kim, G. Joo, H. Jang, M. Jeong, A. Hornig and M. Gude. Glass-fiber mat/PA6 composite tubes subjected to dynamic axial crush loading - Experimental evaluation and high fidelity modeling of failure phenomena. Composite Structures, Vol. 319, 2023. [2] P. Maimí, P.P. Camanho, J.A. Mayugo, C.G. Dávila. A continuum damage model for composite laminates: Part I - Constitutive model. Mechanics of Materials, Vol. 39 (10), 2007. [3] M. David, A. F. Johnson. Effect of strain rate on the failure mechanisms and energy absorption in polymer composite elements under axial loading. Composite Structures, Vol. 122, 2015.